We had examined infiltration and metastasis of colorectal cancer by immunohistochemical staining of laminin. By laminin staining, both nerve fiber fascicles and perineurium are distinctly stained. Therefore, we consider that it is the most suitable staining method for neural invasion of the rectal cancer. To determine the most suitable staining method for neural invasion of the rectal cancer, we performed S-l00, Silver-impregnation, Hematoxylin-Eosin (HE) and laminin staining. The rate of neural invasion shows 58.3%, 19.4%, 25.0% and 47.8%, respectively. By S-100 staining, only nerve fiber fascicles were distinctly stained, and perineurium was obscure. Therefore, we thought that the rate of false positive was increased. By silver-impregnation staining, perineurium and reticular fibers were distinctly stained, and so it was hard to distinguish between perineurium and reticular fibers. By I-lB staining, both perineurium and nerve fiber fascicles were obscure, and it was hard to investiga
… Morete the neural invasion of small nerve. By laminin staining, both nerve fiber fascicles and perineurium were distinctly stained, and we considered that laininin staining was the most suitable method for neural invasion of the rectal cancer. By lam mm staining, we classified the neural invasion on three types (perineural space type : 52.0%, nerve fiber fascicle type : l0.7% and mixed type : 37.3%), and we considered that perineural space type was the most important type of neural inVasion for rectal cancer.We compared with other histopathological factors and neural invasion. Neural invasion was strongly correlated with the depth of invasion, venous invasion and lymph node metastasis. The overall local recurrence rate was 16.6%. A significantly higher frequency of local recurrence (26.7%) was observed in neural invasion positive cases, compared with neural invasion negative cases (7.3%). The cumulative 7-year survival rate for neural invasion negative cases (77%) was significantly higher than that for neural invasion positive cases (39%).Neural invasion was considered a predictor of the local recurrence and prognosis of the rectal cancer, and it is important to examine the neural invasion for determine the treatment policy. We want to add a further examination to elucidate of mechanisms of neural invasion. Less